Engineering Commons^™

Acoustic-Emission Monitoring Of Lap Joint Fatigue Cracks, Siddharth Kannan

Theses and Dissertations

Structural integrity is a pivotal consideration in the field of engineering applications, and understanding the behavior of materials and joints under various loading conditions is critical. This thesis presents a novel approach to detect and analyze fatigue induced cracks in various test specimens using Piezoelectric Wafer Active Sensors. This approach is widely used in Structural Health Monitoring applications involving acoustic emissions that can be captured using PWAS which in turn gives the surface response to applied stresses. The ultimate goal of the research is to identify the length of a fatigue crack originating from lap joints and to develop a …

Accurate Orientation Control Of Tendon Driven Continuum Robots That Exhibit Elasticity, Manu Srivastava

All Dissertations

This dissertation makes new contributions to the modeling and implementation of Tendon Driven Continuum Robots (TDCRs). Specifically, motivated by 3D printing of concrete using a continuum hose robot in construction applications, we focus on TDCRs featuring compliance in the robot backbone and actuating tendons, e.g. surgical robots/endoscopes/catheters with tendon actuation. We expand previous mechanics-based models to show how and why such compliance significantly restricts performance when traditional kinematics-based planning and control techniques are applied.

The main contribution of this work is a new Elasticity Compensation(EC) model that explains why the ad hoc approach of preloading/pretensioning the tendons compensates for compliance …

Mechanics Desktop Lab Equipment, Dante Azpilcueta, Quentin F. Mormann, Arfan Ansar

Mechanical Engineering

This paper overviews the design, implementation and testing of a senior project designed to fix the issue of there being no lab equipment or space for content pertaining to mechanic of materials topics. This is of concern as Cal Poly is reorganizing content as it switches to the semester system and is in need of labs for this material. The solution found was to create a portable miniature universal test machine that could be carted into non-lab classrooms. The goal was to create a device that was low-cost, modifiable, durable, easy to manufacture and repair as these were the qualities …

Effects Of Polymer Side-Group Size On Interfacial Mechanics Of Graphene-Polymer Nanocomposites, Grace Brokaw

All Theses

Graphene-reinforced polymer nanocomposites possess excellent mechanical, thermal, and electrical properties, which make them promising candidates for various applications. Favorable interfacial interactions and mechanics between graphene sheets and polymer matrices are often essential to achieve superior mechanical properties. Nevertheless, it remains largely elusive how molecular features of polymer systems, particularly the side-group size of polymer chains, affect the interfacial mechanics between graphene sheets and polymer matrices, primarily due to challenges in well controlling these features in experiments. On the other hand, exploring their roles in the mechanical properties of graphene-polymer nanocomposites is very expensive to study with all-atomistic molecular dynamics (MD) …

Mechanical Behavior Of Materials, Joshua P. Steimel

Pacific Open Texts

This text serves to cover in more detail solid mechanics concepts and specifically the material response to stress and strain. This text spans solid mechanics concepts from stress and strain at an atomistic length scale, to linear elasticity, anisotropy, linear viscoelasticity, plasticity, dislocation generation and interactions, and fracture.

A Multi Physics Integrated Solution For A High-Pressure Stage Turbine Efficiency And Durability, Sanjay Chopra

Theses and Dissertations

World electricity demand is projected to grow at an annual rate of ~ 2.1% to year 2040₁. EIA projects nearly 50% increase in world energy usage by 2050 led by growth in Asia.[28];[29]. It is predicted that the global electricity demand grows at approximately 1.6 % per year from approximately 2008 and forecasted to approximately 2035, twice the rate of primary energy demand. This raises electricity's usage in total final energy consumption from approximately 19% in 2018 to approximately 24% in 2040. Electricity demand growth is set to be particularly strong in developing economies. .[28];[29];[38] As an enabler, to meet …

The Beautiful Math Of Everything And You Included, E. Ozie

The STEAM Journal

This a reflection on how there is beautiful math to everything. An author's interpretation of matrices and mechanics in its relationship to someone's identity.

Conical Orbital Mechanics: A Rework Of Classic Orbit Transfer Mechanics, Cian Anthony Branco

Mechanical & Aerospace Engineering Theses & Dissertations

Simple orbital maneuvers obeying Kepler’s Laws, when taken with respect to Newton’s framework, require considerable time and effort to interpret and understand. Instead of a purely mathematical approach relying on the governing relations, a graphical geometric conceptual representation provides a useful alternative to the physical realities of orbits. Conic sections utilized within the full scope of a modified cone (frustum) were employed to demonstrate and develop a geometric approach to elliptical orbit transformations. The geometric model in-question utilizes the rotation of a plane intersecting the orbital frustum at some angle β (and the change in this angle) in a novel …

Heavenly Bodies Rsvp, Justin Tyler Spitzer, Allison Jean Turnbaugh, Jack William Boulware, Braden Alex Lockwood

Mechanical Engineering

The purpose of the Heavenly Bodies RSVP project was to design and fabricate planet props, as well as a mechanism by which they could be raised and lowered in California Polytechnic State University’s Pavilion theater. The project team was comprised of four fourth year mechanical engineering students: Allison Turnbaugh, Braden Lockwood, Jack Boulware, and Justin Spitzer. We conducted extensive research to determine the ideal solution for the design problem brought to us by our sponsor. In our analysis, we discovered that the most important aspects of our design were the absolute reliability of the system, fire retardant material selection, and …

Autojack - Hydraulic Powertrain System, Tyce Vu

All Undergraduate Projects

A primary problem for mechanics and automotive enthusiasts is the risk associated with lifting and securing a vehicle with conventional jack stands. Often times, improper jack-stand installation results in the vehicle collapsing unexpectedly, causing injury and/or death. This problem can be minimized through the application of a newly re-designed vehicle lifting system. The conventional method for lifting cars is time consuming and can be unsafe in many circumstances. A better, safer, and more efficient lift design was needed; the AutoJack. The approach of the AutoJack design was entirely focused on the safety of lifting a vehicle. Safety was improved by …

Hemodynamics And Wall Mechanics After Surgical Repair Of Aortic Arch: Implication For Better Clinical Decisions, Siyeong Ju, Ibrahim Abdullah, Shengmao Lin, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Graft repair of aortic coarctation is commonly used to mimic the physiological aortic arch shape and function. Various graft materials and shapes have been adopted for the surgery. The goal of this work is to quantitatively assess the impact of graft materials and shapes in the hemodynamics and wall mechanics of the restored aortic arch and its correlation with clinical outcomes. A three-dimensional aortic arch model was reconstructed from magnetic resonance images. The fluid–structure interaction (FSI) analysis was performed to characterize the hemodynamics and solid wall mechanics of the repaired aortic arch. Two graft shapes (i.e., a half-moon shape and …

Mechanical Characterization Of Anisotropic Fused Deposition Modeled Polylactic Acid Under Combined Monotonic Bending And Torsion Conditions, Aaron T. Santomauro

Honors Undergraduate Theses

Mechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected to multiple monotonic loading conditions. Although empirical data has previously been captured for multi-oriented PLA under tensile and compressive loading conditions, the data has yet to be applied with regard to a representative component …

Tortuosity Calculations, Blood Flow Simulations, And Mechanical Testing Of Mouse Aortae, Shawn Pavey, Jessica Wagenseil

Undergraduate Research Symposium Posters

Aortic aneurysms can lead to wall rupture or dissection, which are both deadly occurrences. The risk of developing problematic aneurysms increases with age, making them a growing concern in the USA’s aging population. Thoracic Aortic Aneurysm (TAA) treatment is highly effective if the TAA is diagnosed in time, however current surgical guidelines catch less than half of fatal TAA cases. Tortuosity (related to vessel length divided by the straight distance between two points of interest) has been proposed as a supplement to diameter based diagnosis of severity of TAA progression. This study aimed to confirm the validity of that proposal …

Constitutive Modeling Of Creep In Leaded And Lead-Free Solder Alloys Using Constant Strain Rate Tensile Testing, Eric Thomas Stang

Browse all Theses and Dissertations

Environmental and safety concerns have necessitated a phase-out of lead-based alloys, which are often used in electronics solder applications. In order to properly assess suitable replacement materials, it is necessary to understand the deformation mechanisms relevant to the application. In the case of electronics solder, creep is an important mechanism that must be considered in the design of reliable devices and systems. In this study, Power-Law and Garofalo constitutive creep models were derived for two medium temperature solder alloys. The first alloy is known by the commercial name Indalloy 236 and is a quaternary alloy of lead, antimony, tin, and …

Reaching In Clutter With Whole-Arm Tactile Sensing, Advait Jain, Marc D. Killpack, Aaron Edsinger, Charles Kemp

Faculty Publications

Clutter creates challenges for robot manipulation, including a lack of non-contact trajectories and reduced visibility for line-of-sight sensors. We demonstrate that robots can use whole-arm tactile sensing to perceive clutter and maneuver within it, while keeping contact forces low. We first present our approach to manipulation, which emphasizes the benefits of making contact across the entire manipulator and assumes the manipulator has low-stiffness actuation and tactile sensing across its entire surface. We then present a novel controller that exploits these assumptions. The controller only requires haptic sensing, handles multiple contacts, and does not need an explicit model of the environment …

Meng 3250: Mechanics Of Elastic Bodies—A Peer Review Of Teaching Project Benchmark Portfolio, Jinying Zhu

UNL Faculty Course Portfolios

This portfolio focuses on mechanics of materials (course title: Mechanics of Elastic Bodies), a sophomore level course taken primarily by civil engineering and architectural engineering majors on Omaha campus. It is a prerequisite for broad range of courses in mechanical, civil and agricultural engineering majors. This course studies the mechanics of solids with applications to science and engineering, including stress, strains and deformation in structural elements (axial, torsional and bending), shear and moment diagram for beams, and a brief introduction to material failure mechanisms.

This portfolio describes the teaching methods used to help students understand the fundamental knowledge about material …

Finite Element Simulation Of Single-Lap Shear Tests Utilizing The Cohesive Zone Approach, Wilson A. Perez

Honors Undergraduate Theses

Many applications require adhesives with high strength to withstand the exhaustive loads encountered in regular operation. In aerospace applications, advanced adhesives are needed to bond metals, ceramics, and composites under shear loading. The lap shear test is the experiment of choice for evaluating shear strength capabilities of adhesives. Specifically during single-lap shear testing, two overlapping rectangular tabs bonded by a thin adhesive layer are subject to tension. Shear is imposed as a result. Debonding occurs when the shear strength of the adhesive is surpassed by the load applied by the testing mechanism. This research develops a finite element model (FEM) …

Automated Tracking And Estimation For Control Of Non-Rigid Cloth, Marc D. Killpack

Faculty Publications

This report is a summary of research conducted on cloth tracking for automated textile manufacturing during a two semester long research course at Georgia Tech. This work was completed in 2009. Advances in current sensing technology such as the Microsoft Kinect would now allow me to relax certain assumptions and generally improve the tracking performance. This is because a major part of my approach described in this paper was to track features in a 2D image and use these to estimate the cloth deformation. Innovations such as the Kinect would improve estimation due to the automatic depth information obtained when …

Visualizing Mechanics: Improving Student Learning Through Video Demonstrations, Blake A. Wetherton, Olumide A. Awofeso, Carolyn E. Creighton, Adam F. Potrzebowski, Charles M. Krousgrill, Jeffrey F. Rhoads

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Purdue Mechanics Freeform Classroom (PMFC) is a project that seeks to reform engineering mechanics education by integrating content and technology; enhancing communication between students, their peers, and instructors; accommodating a broader range of learning styles; and facilitating greater depths of understanding. In an attempt to increase the PMFC’s efficacy, a series of demonstration videos has been produced. As demonstrated by the popularity and pervasiveness of websites such as YouTube, short videos have the potential to captivate audiences. As such, these videos have incredible promise in educational contexts. In the PMFC series of videos, entitled Visualizing Mechanics, each imitates the …

The Mechanics Of Intracranial Loading During Blast And Blunt Impacts – Experimental And Numerical Studies, Veera Selvan Kuppuswamy

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Head injuries in an explosion occur as a result of a sudden pressure changes (e.g. shock-blast) in the atmosphere (primary injury), high velocity impacts of debris (secondary injury) and people being thrown against the solid objects (tertiary injury) in the field. In this thesis, experimental and numerical approaches are used to delineate the intracranial loading mechanics of both primary (blast) and tertiary injuries (blunt).

The blast induced head injuries are simulated using a fluid-filled cylinder. This simplified model represents the head-brain complex and the model is subjected to a blast with the Friedlander waveform type of loading. We measured the …

Spring 2011: Engr 2320: Mechanics Of Solids And Structures: Information About Course: Course Syllabus, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Spring 2011 Engr 2320: Mechanics Of Solids And Structures: Information About Course: Course Schedule, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Spring 2011 Engr 2320: Mechanics Of Solids And Structures: Course Materials: Final Project Instructions, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Spring 2011 Engr 2320: Mechanics Of Solids And Structures: Course Materials: Robot Leg Exercise, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Spring 2011 Engr 2320: Mechanics Of Solids And Structures: Course Materials: Exam 1, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Spring 2011 Engr 2320: Mechanics Of Solids And Structures: Course Materials: Final Exam, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Spring 2011 Engr 2320: Mechanics Of Solids And Structures: Course Materials: Exam 2, Christopher Lee

Christopher Lee

This course covers the principles of statics of structures and mechanics of materials. The focus is on the concepts of stress and strain as related to applied loads (axial, shear, torsion, bending) and to resulting deformation. Students will learn how the principles of mechanics can be applied to mechanical design through modeling, quantitative analysis, strain gauge measurements, and computational simulation. The use of a commercial finite element package is introduced.

Micromechanical Simulation For Fatigue Damage Incubation, Tong Li

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Micromechanical simulations are conducted to quantify the influence of microstructure attributes to the formation of small fatigue cracks. Three wrought aluminum alloys (7075-T651, 2024-T3, virtual material) with fractured particle are studied to quantify the influence of material’s yield strength and ultimate strength to material’s fatigue resistance. Laser Engineered Net Shaping (LENS) material with pores of various spatial distribution and particles are simulated for the microplasticity and its effects on fatigue incubation.

A cohesive zone model is used to study the interface cohesive behavior’s influence to the cyclic driving mechanisms. Different simulations based on different interfacial crack geometries and particle shapes …

Explicit Finite Element Modeling Of Knee Mechanics During Simulated Dynamic Activities, Mark A. Baldwin

Electronic Theses and Dissertations

The natural knee is one of the most commonly injured joints in the body due to relatively high loads and motions that can lead to debilitating degenerative diseases such as osteoarthritis. Total knee arthroplasty is a clinically successful method for eliminating pain in the osteoarthritic knee, but is subject to complications that can affect patient satisfaction and long-term implant performance. The work presented in this dissertation is a demonstration of how anatomic three-dimensional (3D) computational knee models can be an effective alternative for investigating knee mechanics when compared to the cost and time prohibitive nature of in-vivo and in-vitro methods. …

Civil And Mechanical Engineering Students Learning Mechanics In A Multidisciplinary Engineering Foundation Spiral, Jean Nocito-Gobel, Gregory Broderick, Samuel Bogan Daniels, Michael Collura, Richard Stanley

Engineering and Applied Science Education Faculty Publications

This paper describes how mechanical and civil engineering students are introduced to and develop an understanding of mechanics concepts through a sequence of integrated courses as part of a new curriculum taken during the freshman and sophomore years. The Multi- Disciplinary Engineering Foundation Spiral is a four-semester sequence of engineering courses, matched closely with the development of students’ mathematical sophistication and analytical capabilities and integrated with course work in the sciences. Students develop a conceptual understanding of engineering basics in this series of courses, which stress practical applications of these principles. Mechanics concepts are introduced in a pair of first …